decreased nitric oxide synthase level abnormal nitric oxide synthase 2 to nitric oxide synthase 3 ratio decreased nitric oxide synthase 2 to nitric oxide synthase 3 ratio 2022-01-11T21:41:05Z MP:0021080 decrease in the ratio of the concentrations of nitric oxide synthase 2 and nitric oxide synthase 3, two of the enzymes that catalyze the synthesis of nitric oxide from L-arginine reduced NOS2/NOS3 ratio decreased iNOS/eNOS ratio